They were lucky ! fortunately there are some very powerful 10mm hard cast ammo with heavy bullets out there Underwood, Buffalo Bore, Doubletap to name a few. If you are casting your own LBT bullet designs (Veral Smith) LBT burned down in late 2022 and in 2024 he had a stroke, Magma Engineering (my child hood friends) retired this March, equipment sold, best casting equipment ever made and they also bought out Star size lubricator and made those also along with other machining & fabrication, there are other mold makers out there hopefully will take up the slack, but if you can find any LBT molds or Magma Molds I would highly suggest getting them now from any other source before you can't, a side note the LBT molds I have are all hand cast made from (aluminum), Magma molds are special Iron and are specifically cut for Magma high speed automated equipment or the smaller Master Caster. Seems like most of the old school guy's are gone, some of the new lead bullets are now powder coated, I'm sorry they look butt ugly when coated over lube grooves IMO, there are some un-grooved cast molds out there designed for powder coat or plating. sorry got side tracked there.